The present invention relates in general to a closing ring for open head drum-styled containers. Containers of the type disclosed herein may range from the smaller pail sizes of approximately 1 gallon up to much larger industrial drum sizes. The closing ring is used to securely attach a matching closing lid to the open end of the container. Containers of the type disclosed herein, formed as generally cylindrical structures with an upper, generally circular open end, are closed by tightly securing a matching lid over the open end of the container. The lid edge and container lip edge are clamped together by the closing ring. It is important to tightly connect the lid to the container in order to close and seal in the container contents and prevent any loss or leakage of those contents. The closing ring is used in cooperation with the lid and container structures for this purpose.
Since the entire contents of the container may not always be dispensed when the drum (container) is first opened after initial filling, it is important to be able to re-close the container with the matching lid with the same degree of security and tightness that was achieved at the time of initial filling and closing. Presently, the two most commonly-used closing ring structures employ either a tightening bolt arrangement or an over-center lever and linkage arrangement. The bolt arrangement requires manual tightening and untightening of the bolt into or out of a nut or at least an internally-threaded block. The torque applied to the bolt and the relative sizing of the ring body relative to the diameter of the lid dictate the degree of tightness and thus the security of the lid-to-container connection. Once the lid is securely tightened onto the container by this bolt arrangement, it remains in position and is generally not at risk of loosening or coming apart. Perhaps the only risk in terms of loosening is due to vibration during shipment. The benefit of normally remaining tightly secured is offset by the time required to open and close the ring and thereby be able to remove or reapply the lid.
The over-center lever and linkage arrangement uses a linkage with multiple pivots and a lever handle that is folded to close the container and unfolded or pivoted outwardly to be able to open the container. The lever handle in cooperation with the pivot points and linkage members makes use of the mechanical advantage and leverage of the structure to enable a tight closing operation, while still being done manually. By enabling the manual folding of the lever handle to apply a sufficient clamping force by means of the closing ring to properly secure the lid to the container, the time required to unthread or thread the clamping bolt of the other configuration is eliminated. The tighter the clamping force applied by the closing ring, the greater the level of manual force that must be applied to the lever handle.
Prior to the present invention, in order to actually secure this lever and linkage style of closing ring in its closed condition, it was necessary to apply some external accessory such as a locking pin or tie. This type of accessory needs to be manually applied when the container is filled and closed and then removed at the time of initial dispensing. If the contents are not dispensed completely from the container after initial opening, and if there is some risk that the closing ring would inadvertently open, then the selected locking pin or tie would need to be reassembled, perhaps using a new one, and the process would then repeat itself whenever the container was opened on subsequent occasions. Whether done once or multiple times, this particular approach represents a time investment that would offset some of the benefits derived from the simplicity of the fold-to-close (over-center) lever and linkage arrangement. The concern is that without some type of securing or locking feature, the lever handle can be inadvertently flipped over to an open condition. This could occur unintentionally or it could occur inadvertently if the lever handle is caught or hooked on some other structure. This is possible during handling, loading, shipping, storage, etc. It would therefore be an improvement to this current state of the art in container closing rings to be able to retain the reliability and simplicity of the fold-to-close linkage but add a simple and effective securing or locking feature to prevent unintentional or inadvertent opening of the closing ring. The objective is to preclude the need for any hand tool or other implement and to eliminate the use of any add-on or extra component part or accessory. While these benefits are being achieved, the simplicity, strength, and reliability of the lever and linkage arrangement should not be compromised. As disclosed herein, the present invention includes an effective securing or locking feature as part of a simple, strong, and reliable closing ring construction.